Abstract: The rates of photosynthesis,respiration and transpiration of three mangrove plants growing at Aotou Port of Daya Bay were determined.The results show that the diurnal changes of photosynthetic rates present curves of two-peak,The order of means are Agiceras corniculatum >Bruguiera gymnorrhiza >Avicennia marina.The Change ranges of respiratory rates are smaller than that of photosynthetic rates of all three species.Different from photosynthesis,the order of means of respiratory rates are A.Corniculatum >A.marina >B.gymnorrhiza.These suggust that A.marina has the lowest productivity among the three species and it may be related to the harsher habitat which A.marina grows.Transpiration rates appear curves of one peak.Due to the salt-secreting or salt-excuding species,the means of A.corniculatum is close to A.marina and higher than that of B.gymnorrhiza.In general,these three mangrove plants have high photosyntic rates,low respiratary and transpiration rates and are survivals of the special habitat of salt and inundation.

Key words: Mangrove, eco-physiology, Daya Bay